The present invention is an apparatus and method for hydrating and freezing superabsorbent polymer based refrigerant media similar to that disclosed in international patent application number PCT/US92/06486 (in reference to U.S. App. Ser. No. 07/738835), herein incorporated for reference, or similar media which is used to keep perishable materials at a controlled, cool or freezer temperature during shipment. Accordingly, discussion of the structure and properties of the media disclosed in the referenced patent shall be discussed in detail only to the extent necessary to explain the media's interaction with the components of the apparatus and method herein described, and inasmuch as a detailed understanding of the chemical properties of the media are not necessary for an understanding of the invention.
Prior to using superabsorbent polymers laminated into individual cells, shipping containers utilized only a few substances to maintain a cool temperature inside a shipping container. These include: ice in sealed pouches, dry ice, and gel blocks. However, for reasons such as high cost, contamination and handling problems, and an inability to maintain critical temperatures in a container during shipment, these shipping materials have begun to be replaced with frozen, superabsorbent polymer based refrigerant media [hereinafter media]. One such media is ThermaFreeze.RTM. made by Thermafreeze, Inc. of Mobile, Ala. ThermaFreeze.RTM. is manufactured in long rolls, typically in 15 or 30 inch widths, containing a matrix of laminated individual cells between elongated continuous sheets of thermoformable media, as disclosed in the referenced patent. Each cell contains a measured amount of superabsorbent polymer capable of absorbing water to many times its own weight and size, thereby filling each cell upon exposure to water. Prior to exposure of the cells to an aqueous environment, the cells in the rolls are filled with the superabsorbent polymer powder which occupies negligible space inside the cells. Therefore, prior to hydration the cells are un-expanded and the media consists of a flat sheet or web of cells typically 15 or 30 inches wide and of a preselected length (typically 300 feet).
In one preferred operation, a media roll must be unwound, exposed to an aqueous environment suitable to quickly hydrate the media, frozen, and cut into shapes and sizes suitable for arrangement within shipping containers. This preparation operation may be established "on-site" within a production facility for a user consuming the media in shipping operations. However, current methods for preparing the media are manually based and, therefore, time consuming; thereby increasing the overall cost of utilizing the media in shipping operations. Furthermore, the consumer may not have the necessary know how to optimize the preparation operation so that the media is suitably prepared for incorporation within shipping containers of varying sizes and shapes. In addition, a variety of other uses may be made of the product, but for the lack of proper knowledge and a feasible automation facility.
Therefore, there is a need in the shipping packaging, and other industries for an apparatus and method for automating the preparation of superabsorbent polymer refrigerant media prior to arrangement into shipping containers. Inasmuch as many facilities place a premium on the use of floor space, a modular unit which has a relatively small "footprint" is important.